Electronic Paper Device And Manufacturing Method Thereof

ABSTRACT

This present invention provides an electronic paper display device. The electronic paper display device includes a thin film transistor array substrate and a display panel disposed on one side of the thin film transistor array substrate. The thin film transistor array substrate comprises a first substrate, a first metal layer, a dielectric layer, a second metal layer, a channel layer, a pixel electrode layer, a protection layer, a first resin layer and a second resin layer. The display panel includes a second substrate, a transparent electrode layer disposed on the second substrate, and an electronic ink material layer between the transparent electrode layer and the thin film transistor array substrate.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuational of U.S. application Ser. No.13/006,629, filed on Jan. 14, 2011, which was based on, and claimspriority from, Taiwan Patent Application Serial Number 099126338, filedAug. 6, 2010, the disclosure of which is hereby incorporated byreference herein in its entirely.

BACKGROUND

1. Field of Invention

The present invention relates to an electronic paper device andmanufacturing method thereof. More particularly, the present inventionrelates to an electronic paper device that can prevent hitting damageand a manufacturing method to manufacture this device.

2. Description of Related Art

With the improvement of techniques for manufacture and design, many newdisplay apparatus is developed, wherein the electronic paper displaydevice presents many advantages including lower energy consumption,longer lifetime, and smaller size.

The electronic paper display device was developed in the 1970s. One ofthe major characteristic of the display device is incorporation ofelectrically charged micro-spheres with half of it being painted withwhite color and the other half being painted with black color. When anelectric field is adjusted, the sphere will rotate top to bottom andhence display a different color. In the second generation of electronicpaper display device developed in the 1990s, mini capsules have replacedthe micro-spheres. Colored oil and charged white particles fill the minicapsules. The white particles can move to the top or sink to the bottomunder a controlled electric field. When the white particles rise to thetop (move closer to the reader), a white color is displayed. On theother hand, when the white particles sink to the bottom (away from thereader), the color of the oil is displayed.

However, the display panel substrate is adhered to the thin filmtransistor (TFT) array substrate. That is, no buffer structure is builtbetween the display panel substrate and the TFT array substrate.Therefore, when the display panel substrate is hit, the force willdirectly transmit to the TFT array substrate to damage the thin filmtransistors in the TFT array substrate.

Therefore, a structure that can protect the thin film transistors in theTFT array substrate is needed.

SUMMARY

This present invention provides an electronic paper device andmanufacturing method thereof. An additional resin layer is formedbetween the display panel substrate and the TFT array substrate. Theresin layer acts as a buffer layer to disperse force from the displaypanel substrate to protect the TFT array substrate.

This present invention provides an electronic paper display device. Theelectronic paper display device includes a thin film transistor arraysubstrate and a display panel disposed on one side of the thin filmtransistor array substrate. The thin film transistor array substratecomprises a first substrate, a first metal layer, a dielectric layer, asecond metal layer, a channel layer, a pixel electrode layer, aprotection layer, a first resin layer and a second resin layer. Thefirst metal layer disposed on the first substrate, wherein the firstmetal layer includes a plurality of scan lines and a plurality of gateelectrodes electrically connected to the scan lines. The dielectriclayer disposed on the first substrate and covers the first metal layer.The second metal layer disposed on the dielectric layer, wherein thesecond metal layer includes a plurality of data lines, a plurality ofsource electrodes electrically connected to the data lines and aplurality of drain electrodes. The channel layer disposed over thedielectric layer and among the source electrodes, the gate electrodesand the drain electrodes. The protection layer disposed on the secondmetal layer and the channel layer. The first resin layer disposed on theprotection layer. The pixel electrode layer disposed on the first resinlayer, wherein the pixel electrode layer includes a plurality of pixelelectrodes. The second resin layer disposed on the pixel electrodelayer. The display panel includes a second substrate, a transparentelectrode layer disposed on the second substrate, and an electronic inkmaterial layer between the transparent electrode layer and the thin filmtransistor array substrate.

In an embodiment, the data lines and the scan lines divide the firstsubstrate into a plurality of pixels, wherein the pixel electrode layerare located within the pixels respectively.

In an embodiment, the second resin layer is formed over the whole thinfilm transistor array substrate to cover the scan lines, the data linesand the pixel electrode layer.

In an embodiment, the second resin layer is a matrix structure, and thesecond resin layer covers the pixel electrode layer and does not coverthe scan lines and the data lines.

In an embodiment, the second resin layer has a pattern as a Chinesecharacter

, wherein the second resin layer cover the scan lines and the data linesand does not cover the pixel electrode layer.

In an embodiment, the second resin layer includes a plurality ofislands.

In an embodiment, the second resin layer has a thickness from 0.5 um to10 um.

In an embodiment, the material for forming the second resin layer is apositive photoresist or a negative photoresist.

In an embodiment, the material for forming the second resin layer is anEthylene-Vinyl Acetate copolymer, EVA.

In an embodiment, the material for forming the second resin layer is amixed material of resin and an inorganic material.

This present invention also provides a method for forming an electronicpaper display device. The method includes sequentially forming a firstmetal layer, a dielectric layer, a second metal layer, a channel layer,a protection layer, a first resin layer, a pixel electrode layer and asecond resin layer on a first substrate to form a thin film transistorarray substrate. A transparent electrode layer is formed on a secondsubstrate. An electronic ink material layer between the transparentelectrode layer and the thin film transistor array substrate.

In an embodiment, the data lines and the scan lines divide the firstsubstrate into a plurality of pixels, wherein the pixel electrode layerare located within the pixels respectively.

In an embodiment, the second resin layer is formed over the whole thinfilm transistor array substrate to cover the scan lines, the data linesand the pixel electrode layer.

In an embodiment, the second layer is a matrix structure, and the secondlayer covers the pixel electrode layer and does not cover the scan linesand the data lines.

In an embodiment, the second resin layer has a pattern as a Chinesecharacter

, wherein the second resin layer cover the scan lines and the data linesand does not cover the pixel electrode layer.

In an embodiment, the second resin layer includes a plurality ofislands.

In an embodiment, the second resin layer has a thickness from 0.5 um to10 um.

In an embodiment, the material for forming the second resin layer is apositive photoresist or a negative photoresist.

In an embodiment, the material for forming the second resin layer is anEthylene-Vinyl Acetate copolymer, EVA.

In an embodiment, the material for forming the second resin layer is amixed material of resin and an inorganic material.

Accordingly, an additional second resin layer is formed over the pixelelectrode layer. The second resin layer acts as a buffer layer toprotect the thin film transistor in the thin film transistor arraysubstrate free from hit damage. For example, when the display panelsubstrate is hit, the second resin layer can disperse this hit force toreduce the force hit the thin film transistor on the thin filmtransistor array substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the followingdetailed description of the embodiments, with reference made to theaccompanying drawings as follows:

FIG. 1A is a cross-sectional view along line A-A′ of FIG. 1B.

FIG. 1B is a top view of a thin film transistor (TFT) array substrate.

FIG. 2 illustrates a first metal layer formed in a first substrate.

FIG. 3 illustrates a dielectric layer formed over the first metal layer.

FIG. 4 illustrates a channel layer defined over the dielectric layer anda second metal layer formed over the dielectric layer.

FIG. 5 illustrates to form a protection layer and a first resin layer.

FIG. 6 illustrates a second resin layer formed over the pixel electrodelayer.

FIG. 7 illustrates a second resin layer with a matrix structure.

FIG. 8 illustrates a second resin layer with a structure as a Chinesecharacter

.

DETAILED DESCRIPTION

FIG. 1B is a top view of a thin film transistor (TFT) array substrate.FIG. 1A is a cross-sectional view along line A-A′ of FIG. 1B. As shownin FIGS. 1A and 1B, the electronic paper display device 100 includes athin film transistor array substrate 200 and a display panel 300disposed on one side of the thin film transistor array substrate 200.

The thin film transistor array substrate 200 comprises a first substrate210, a first metal layer 220, a dielectric layer 230, a second metallayer 240, a channel layer 250, a pixel electrode layer 260, aprotection layer 270, a first resin layer 280 and a second resin layer290.

The first metal layer 220 and the dielectric layer 230 are disposed overthe first substrate 210. The dielectric layer 230 covers the first metallayer 220. The first metal layer 220 forms the scan lines 222 and gateelectrodes 224 electrically connected to the respective scan lines 222.The second metal layer 240 is disposed on the dielectric layer 230. Thesecond metal layer 240 forms data lines 242 and source electrodes 244and drain electrodes 246. The protection layer 270 covers the secondmetal layer 240. The first resin layer 280 covers the protection layer270. The pixel electrode layer 260 is disposed on the first resin layer280. A through hole 282 is formed in the first resin layer 280 and theprotection layer 270 to expose partial region of the drain electrode 246in the pixel region 212. The pixel electrode layer 260 is electricallyconnected to the second metal layer 240 through the through hole 282.The second resin layer 290 is disposed on the pixel electrode layer 260to act as a buffer layer to protect the thin film transistor in the thinfilm transistor array substrate free from hit damage. The data lines 242and the scan lines 222 divide the first substrate 210 into a pluralityof pixel areas 212. The gate electrodes 224, the source electrodes 244and the drain electrodes 246 are disposed inside the respective pixelareas 212. The channel layer 250 is disposed on the dielectric layer 230between the gate electrode 224, the source electrode 244 and the drainelectrode 246. The pixel electrode layer 260 is disposed inside thepixel area 212 and electrically connected to respective drain electrode246.

The display panel 300 includes a second substrate 310, a transparentelectrode layer 320 disposed on the second substrate 310, and anelectronic ink material layer 330 between the transparent electrodelayer 320 and the thin film transistor array substrate 200. Thetransparent electrode layer 320 is fabricated using indium tin oxide(ITO), indium zinc oxide (IZO) or other transparent conductive material,for example. The electronic ink material layer 330 has a plurality ofmini capsules 332 and each capsule 332 includes black paint, white paintand a transparent fluid, for example. The display panel substrate 300 isadhered to the thin film transistor array substrate 200 through anadhering layer 334. In addition, through changing the electric fielddirection between the pixel electrode layer 260 and the transparentelectrode layer 320, the paint can move up or down according to thedirection of the electric field. As a result, the various pixels in theelectronic ink display device 400 display a black or a white color. Thethickness of the second resin layer 280 is increased to avoid anadditional electric field between the second metal layer 240 and thetransparent electrode layer 320 being generated to affect the movementof the capsules 332.

FIG. 2 to FIG. 6 illustrate a manufacturing process of a thin filmtransistor array substrate 200. FIGS. 1A and 1B are also referred.

Referring to FIG. 2 first, a first metal layer 220 is formed on a firstsubstrate 100. The material used for the first substrate 210 can be aglass or a transparent insulating plastic. The material used for thefirst metal layer 220 is chromium (Cr), copper (Cu) or Cu—Cr alloy.Generally, the material used for the first metal layer 220 is formed onthe first substrate 210 first. Then, a photolithography process isperformed to remove the unnecessary material and define the pattern ofthe scan lines 222 and gate electrodes 224.

Next, referring to FIG. 3, a dielectric layer 230 is formed over thefirst metal layer 220 to act as an isolation layer. The dielectric layer230 is formed by plasma enhancement chemical vapor deposition (PECVD).The material of the dielectric layer 230 is a silicon oxide or a siliconnitride (SiNx).

In FIG. 4, a channel layer 250 is formed on a position corresponding toa gate electrode 224 on the dielectric layer 230. Then, an ohmic contactmaterial layer is formed over the channel layer 250. Generally, thechannel layer 250 can be formed by using plasma chemical vapordeposition (PECVD). Then, a photolithography process is performed toremove the unnecessary material and define the pattern of the channellayer 250. The channel layer 250 is an amorphous silicon (a-Si) layer.Then, a second metal layer 240 is formed over the dielectric layer 230and the ohmic contact material layer over the channel layer 250. Thissecond metal layer 240 can be formed by a physical vapor deposition(PVD). Next, a photolithography process and a wet etching process areperformed to pattern the second metal layer 240. An opening 248 isformed on the second metal layer 240 to expose the channel layer 250.The second metal layer 240 located on the two sides of the opening 248is defined as the source electrode 244, the drain electrode 246 and thedata line 242 electrically connected to the source electrode 244. Thematerial used for the second metal layer 240 can be chromium (Cr),copper (Cu) or Cu—Cr alloy.

Referring to FIG. 5, a dry etching process is performed while using thedefined second metal layer 240 as a mask to remove the partial ohmiccontact material layer located on the opening 248. After that, the thinfilm transistor of the present invention is finished. Next, a protectionlayer 270, such as a silicon nitride, is formed on the finishedstructure for preventing moisture from etching the finished structure.Then, a first resin layer 280 is formed over the protection layer 270 toavoid an additional electric field between the second metal layer 240and the transparent electrode layer 320 being generated to affect themovement of the capsules 332. Next, a photolithography process and anetching process are performed to form a through hole 282 in theprotection layer 270 and the first resin layer 280 to expose partialregion of the drain electrode 246. A transparent conducting layer isformed on the first resin layer 280 to serve as a pixel electrode layer260. In a preferred embodiment, an indium tin oxide (ITO) layer is usedas the pixel electrode layer 260. The pixel electrode 260 iselectrically connected to the drain electrode 246 through the throughhole 282.

Finally, referring to FIG. 6, a second resin layer 290 is formed overthe pixel electrode layer 260 by a spin coating method. The second resinlayer 290 acts as a buffer layer to protect the thin film transistor inthe thin film transistor array substrate 200 free from hit damage. Forexample, when the display panel substrate 300 is hit, the second resinlayer 290 can disperse this hit force to reduce the force hit the thinfilm transistor on the thin film transistor array substrate 200. In anembodiment, the second resin layer 290 has a thickness of 0.5 um to 10um. Positive photoresist or negative photoresist is used to form thesecond resin layer 290. In another embodiment, Acrylic resin or a mixedmaterial of resin and Silica gel is used to form the second resin layer290. In a further embodiment, the Ethylene-Vinyl Acetate copolymer, EVA,is used to form the second resin layer 290. In a further embodiment, amixed material of resin and an inorganic material, such as Silicon,Silica, Titania or nano material, is used to form the second resin layer290.

In an embodiment, the second resin layer 290 is formed over the wholethin film transistor substrate 200. That is, no pattern is formed in thesecond resin layer 290. The scan lines 222, the data lines 242, thepixel electrode layer 260 and the thin film transistors are covered bythe second resin layer 290.

In another embodiment, as shown in the FIG. 7, the second resin layer290 is a matrix structure and does not cover the scan lines 222 and thedata lines 242. In other words, in each pixel, the second resin layer290 is formed over the whole pixel electrode layer 260. Therefore, thethin film transistor and the pixel electrode layer 260 are covered bythe second resin layer 290 in each pixel.

In a further embodiment, as shown in the FIG. 8, the second resin layer290 is formed over the scan lines 222 and the data lines 242. That is,the second resin layer 290 has a structure as a Chinese character

. In other words, in each pixel, the second resin layer 290 is formedover the scan lines 222 and the data lines 242. Therefore, the thin filmtransistor and the pixel electrode layer 260 are not covered by thesecond resin layer 290 in each pixel. However, it is noticed that thestructure of the second resin layer 290 is not limited by the foregoingembodiments. For example, the second resin layer 290 includes manyislands. The appearance of islands and the locations of islands formedin the thin film transistor substrate are not limited. Each island canbe a square bump, a diamond bump, a circular bump or a polygon bump.

Accordingly, an additional second resin layer is formed over the pixelelectrode layer. The second resin layer acts as a buffer layer toprotect the thin film transistor in the thin film transistor arraysubstrate free from hit damage. For example, when the display panelsubstrate is hit, the second resin layer can disperse this hit force toreduce the force hit the thin film transistor on the thin filmtransistor array substrate.

Although the present invention has been described in considerable detailwith reference to certain embodiments thereof, other embodiments arepossible. Therefore, it will be apparent to those skilled in the artthat various modifications and variations can be made to the structureof the present invention without departing from the scope or spirit ofthe invention. In view of the foregoing, it is intended that the presentinvention cover modifications and variations of this invention providedthey fall within the scope of the following claims.

1. A display device, comprising: a thin film transistor array substrate,wherein the thin film transistor array substrate comprises: a firstsubstrate; a first conductive layer disposed on the first substrate; adielectric layer covering the first conductive layer; a secondconductive layer disposed on the dielectric layer, wherein thedielectric layer is disposed between the first conductive layer and thesecond conductive layer; a first resin layer; and a pixel electrodelayer, wherein the pixel electrode layer includes a plurality of pixelelectrodes; and a display panel disposed on one side of the thin filmtransistor array substrate and comprising a transparent electrode layer,wherein the first resin layer is deposed between the second conductivelayer and the transparent electrode layer.
 2. The display device ofclaim 1, wherein the thin film transistor array substrate furthercomprises a second resin layer disposed on the pixel electrode layer. 3.The display device of claim 2, wherein the first conductive layerincludes a plurality of scan lines and a plurality of gate electrodeselectrically connected to the scan lines, and the second conductivelayer includes a plurality of data lines, a plurality of sourceelectrodes electrically connected to the data lines and a plurality ofdrain electrodes.
 4. The display device of claim 3, wherein the secondresin layer is formed over the thin film transistor array substrate tocover the scan lines, the data lines and the pixel electrode layer. 5.The display device of claim 3, wherein the second resin layer is amatrix structure, and the second resin layer covers the pixel electrodelayer and does not cover the scan lines and the data lines.
 6. Thedisplay device of claim 3, wherein the second resin layer has a patternas a Chinese character

, wherein the second resin layer cover the scan lines and the data linesand does not cover the pixel electrode layer.
 7. The display device ofclaim 2, wherein the second resin layer includes a plurality of islands.8. The display device of claim 2, wherein the second resin layer has athickness from 0.5 um to 10 um.
 9. The display device of claim 2,wherein the second resin layer is formed by a positive photoresist or anegative photoresist.
 10. The display device of claim 2, wherein thesecond resin layer is formed by an Acrylic resin or a mixed material ofresin and Silica gel.
 11. The display device of claim 2, wherein thesecond resin layer is formed by an Ethylene-Vinyl Acetate copolymer. 12.The display device of claim 2, wherein the second resin layer is formedby a mixed material of resin and an inorganic material.
 13. A displaydevice, comprising: a thin film transistor array substrate, wherein thethin film transistor array substrate comprises: a first substrate; afirst conductive layer disposed on the first substrate; a dielectriclayer covering the first conductive layer; a second conductive layerdisposed on the dielectric layer, wherein the dielectric layer isdisposed between the first conductive layer and the second conductivelayer; a second resin layer; and a pixel electrode layer, wherein thepixel electrode layer includes a plurality of pixel electrodes; and adisplay panel disposed on one side of the thin film transistor arraysubstrate and comprising a transparent electrode layer, wherein thesecond resin layer is deposed between the pixel electrode layer and thetransparent electrode layer.
 14. The display device of claim 13, whereinthe thin film transistor array substrate further comprises a first resinlayer disposed between the second conductive layer and the pixelelectrode layer.
 15. The display device of claim 13, wherein the firstconductive layer includes a plurality of scan lines and a plurality ofgate electrodes electrically connected to the scan lines, and the secondconductive layer includes a plurality of data lines, a plurality ofsource electrodes electrically connected to the data lines and aplurality of drain electrodes.
 16. The display device of claim 15,wherein the second resin layer is formed over the thin film transistorarray substrate to cover the scan lines, the data lines and the pixelelectrode layer.
 17. The display device of claim 15, wherein the secondresin layer is a matrix structure, and the second resin layer covers thepixel electrode layer and does not cover the scan lines and the datalines.
 18. The display device of claim 15, wherein the second resinlayer has a pattern as a Chinese character

, wherein the second resin layer cover the scan lines and the data linesand does not cover the pixel electrode layer.
 19. The display device ofclaim 13, wherein the second resin layer includes a plurality ofislands.
 20. The electronic paper display device of claim 13, whereinthe second resin layer has a thickness from 0.5 um to 10 um.